Modern dishwashers typically include a wash chamber where e.g., detergent, water, and heat can be applied to clean food or other materials from dishes and other articles being washed. Various cycles may be included as part of the overall cleaning process. For example, a typical, user-selected cleaning option may include a wash cycle and rinse cycle (referred to collectively as a wet cycle), as well as a drying cycle. A pre-wash cycle may also be included as part of the wet cycle, and may be automatic or an option for particularly soiled dishes.
In one or more of these cycles, particularly during the drying cycle, it may be desirable to allow heated fluid—typically steam—to be vented from the wash chamber. Such venting allows e.g., for the removal of moisture from the dishes and helps dissipate heat from the drying cycle. Conversely, it is also desirable to retain fluids and heat during other parts of the cleaning process. For example, during the wet cycle, cleaning can be improved by keeping the wash chamber sealed so as to retain heat energy while a heated mixture of water and detergent is sprayed against the dishes and other articles. Maintaining a closed chamber during the pre-wash and wash cycle can also be necessary in order to prevent fluid from being ejected.
Conventionally, one or more vents have been provided near the top of the front door of the dishwasher to allow for the escape of fluid from the wash chamber. In some cases, active vents are utilized. The flow of fluid through such active vents is commonly controlled through a curtain or other cover that is driven by a motor connected through a drive mechanism. The motor must be electrically powered and activated at appropriate times during the cleaning process. As such, this conventional configuration typically adds expense to the manufacture and maintenance of a dishwashing appliance.
Accordingly, in other cases, passive vents are utilized. The flow of fluid through such passive vents is passively controlled based on the configuration of the vents, such as the sizes of the holes defined in the vent. During the wet cycle, water sheets the holes and prevents fluid flow through the vent. During the drying cycle, fluid is allowed to flow through the vent due to the lack of sheeting.
One issue with known passive vent designs is that the surface tension of the water that sheets the holes must be overcome for the water to drain and the holes to open. In some known vent designs, the surface tension of the water can result in the holes remaining sheeted for extended periods of time, such as hours, after venting is desired. One solution to improve the drainage of such vents has been to add vertically extending ribs to the vent, which extend between the horizontally extending vent holes. The ribs facilitate water flow from the holes and thus allow proper water drainage. However, optimal operation of this vent design only occurs when the ribs are positioned vertically. Because vents are typically screwed into dishwasher appliance doors, it is difficult and time consuming to properly orient these vents.
Accordingly, improved vent designs for dishwasher appliances are desired. In particular, passive vents which provide improved liquid flow from apertures thereof, regardless of the orientation of the vent, would be advantageous.